Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

387
FXUS63 KLOT 181126
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
626 AM CDT Thu Jun 18 2026

.KEY MESSAGES...

- Next significant chance of rain is Sunday with potential for
  locally heavy rainfall.

&&

.DISCUSSION...
Issued at 121 AM CDT Thu Jun 18 2026

After a couple of active days, a much quieter weather pattern
expected the next few days. Northwest flow aloft will persist
with high pressure across the Ohio Valley blocking any return
moisture from the Gulf. A couple of subtle/weak perturbations in
the northwest flow will could bring some spotty showers to the
area, mainly Friday night. Coverage is expected to be on the low
side, as is confidence in it raining, so the slight chance to
chance pops offered up by the NBM seem reasonable. Temperatures
the next couple of days will be a bit below average with
comfortable dewpoints generally in the 50s.

For days now, medium range guidance has been in good agreement
in bringing a stronger shortwave trough into the Midwest late in
the weekend. By Saturday, the aforementioned surface ridge is
expected to shift eastward allowing for southerly flow from the
Gulf to advect moisture northward in advance of the next
system. There remains some latitudinal variability and
differences in guidance with respect to the track of the
associated sfc low, but there has been a pretty consistent
signal for a swath of potentially heavy rainfall setting up in
or near our CWA Sunday. Accordingly, NBM pops are quite high
and no changes were needed.

Northwest flow aloft will continue into next week. Drier
weather is expected to start the week in the wake of the Sunday
system. Next chance of showers/storms looks to be toward the
middle of next week. Temperatures next week look to remain near
to slightly below average.

- Izzi

&&

.AVIATION /12Z TAFS THROUGH 18Z FRIDAY/...
Issued at 626 AM CDT Thu Jun 18 2026

Mvfr cigs this morning.
Chance of showers this morning.
Gusty northwest winds this morning.

Mvfr cigs will continue through late morning across the
terminals and a few hours of low mvfr cigs are possible along
with a few showers or sprinkles. Cigs will slowly lift to low
vfr by early this afternoon and then scatter out this evening.

Winds are becoming northwesterly currently and will remain
northwest this morning with gusts into the lower/mid 20kt range.
These gusts will slowly diminish through the late morning and
end this afternoon as directions turn back westerly. Speeds will
diminish under 10kts with sunset this evening. cms

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...Beach Hazards Statement until 3 PM CDT this afternoon for
     INZ002.

LM...Small Craft Advisory until 9 AM CDT this morning for the IL
     and IN nearshore waters.

&&

$$

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